Topic 6: Flashcards

Question

Xerophiles

Answer 1

Love low water activity

Answer 2

Temp affects membrane fluiditiy, enzyme function and macromolecule structure Psychrophiles: -20-10 Mesophiles: 10-60 Thermophiles: 60-80 Hyperthermophiles: 80-120 Optimum temp is the temo that enzymatic reactions occur at max Higher than this leads to protein denaturing lower: membrane gelling so transport process so slow that growth cant occur

Answer 3

Min : <0 optimum: 15 Max: 20 -Unsaturated fatting acids allow for colder temp stability cuz they stay fluid even at low temps so more of this than in mesophiles - found in oceans, etc

Answer 4

0-4 degrees optimum: 20-40 capable of low temp growth ex: ecoli found in soil, house, etc

Answer 5

Supervolcano, boiling springs that are heated above boiling point all temps above 50-60 soil in midsummer compose hotspring deep sea hydrothermal vent hot water heaters

Answer 6

-increased A A bonds produce heat-resistant folds -ionic bonds between acidic and basic residues -certain solutions help stabilize: di-inostol phosphate and diglycerol phosphate -saturated fatty in bacteria -phospholipid monolauyer in archaea more thermotolerant than bilahyer (two head)

Answer 7

Complex Media -unknown composition (IF SAYS YEAST EXTRACT, PEPTONE, TRYPTONONE) Defined media -known composition (GLUCOSE, NACL, ETC)

Answer 8

Selective media -allows for isolation of a specific microbe/s due to specific properties Differential media: -allows different microbes to be identified based on visual reactions with medium ie, colour Enriched media -used to increase a population of microbes with a certain property

Answer 9

On Solid medium easier since cells are held in place and can be isolated 1) Streak plate method 2)spread plate method (glass hockey stick) 3) pour plate method (liquid), not all organisms want to be at this temp

Answer 10

1) Direct Count (Petroff hauser chamber, known amount put on to slide with grid and coverslip, cells counted with viable microscope (CANT DIFFERENTIATE BETWEEN DEAD AND ALIE CELLS) 2) Viable cell Counts (Serial dilutions and CFU's, cultures diulted in series of tubes, and plates (1 in 10, 1 in 100), colonies counted after incubation 3) Turbidity measurements: spectrometer sends light through culture, light absorbance dictates density of cells, less transmittance, more growth

Answer 11

Colony forming units per mL of culture, calculated by multiplying the nuber of colonies by INVERSE of dilution factor (1/1x10^-5)

Answer 12

Lag Phase: preparing for steady growth Exponential phase: Replicating and growing at a steady and constant exponential rate Stationary phase: death rate equal to growth rate or replication Halted Death Phase: nutrients depleted, waste lebels high, so cells are dying at exponential rate

Answer 13

Time it takes to double the population in exponential phase rise/run

Answer 14

numner of generations per unit time (run/rise)

Answer 15

max population density and or amount of cellular material produced by culture

Answer 16

-used to keep micro in exponential growth phase, to harvest one of their producets (kept in limited biut continous flow of nutrients) Chemostat flows in fresh medium and takes out old

Answer 17

1) Filteration: Use different pore size to allow different things in or keep certain things out 0.2 common for sterilization 3 filter types:depth folters (removes big particles first cuz ti doesnt clog) Conventional membrane filter: used for routine sterilization Nucleopore filters: has consistent pore size cuz radiation made the pores, used for microcospy 2) Temperature heat denautres it, 100 degrees kills most Sterilization method; Autoclave used: adds pressure, which keeps fluid from evaporating at high temps, brings temp to 121 without boiling it. Effective on endospores and hyperthermophiles can get it to high heat TO be sterilized, SAMPLE temp must be at 121 for 15 mins ( not autoclave time, but temp of organism) Pasteurization NOT FOR STERILIZATION -reduces microbial long (90-99%) HTST: 72 degrees 15 seconds UHL: 1 second 135 degrees ESL: filter, then pasteur, for increasing shelf Freezing better for long term preservation cuz stops biochem reactions 3) Electrochemical radiation SANITIZATION NOT STERILIZSTION cuz controls microbial grouth on non-living surfaces UV radiation of 260-280nm can damage dna by forming THYMINE DIMERES (cuases frameshift mutations in proteins) Ionization radiation is used: protein damage, dna damage, hydroxides formed,free e-, limited to industries cuz cosstly and hazardous 4) Chemicals Antimicrobial agents: target bacteria, fungi, algi, uiricide -can be non-selective (kills everything, affrct sulfhydryl group which all things have -can be selective (antibiotics affecting euk ribosomes, or penecillin) useful for disease

Answer 18

Bacteriostatic: growth inhibitory (tetracylin, ampicilin Bacteriocidal: kills cells Bacteriolytic: lysis cells ( penicillin)

Answer 19

Ethanol: Membranes Triclosan: Membrane (phenolic) Benzalkonium chloride: Membrane Sodium hypochlorite: oxidizing agent Glutaraldehyde: crosslinks proteins

Answer 20

antimicrobial agents produced by microbes -work by binding to proteins or other cellular organelles to disrupt function Broad spectrum: Tetracycline (both gram neg and gram pos, inhibit protein synthesis) Narrow spectrum: Pennicillin (inhibit cell wall synthesis of gram pos bacteria) Polymyxin B ( Disruption of outer membrane (gram neg)

Answer 21

Time required to kill 90% of the target organism under specific conditions DT is at 300 grays, If we start with 1,000,000 org in culture , how many do we expect to see after exposed to 900 grays? 1000 (take off zeros based on how many times 300 goes into 900)

Answer 22

bacterilytic